Launch operations of the SSME

The mission profile, performance over the first eight flights, and inspection and repair procedures for the Shuttle main engines (SSME) are outlined. The Orbiter has three SSMEs, each delivering 470,000 lb thrust at rated level and 512,000 lb thrust at full power level. The engines each have a design lifetime of 55 launches and 27,000 sec operating life. After eight STS flights the SSME maintenance requirements and part replacements have generally followed those experiences during ground tests, i.e., routine checkout of some items are performed every flight, some after a few flights, and replacements are made as needed or scheduled. Hot-fire tests are performed only if a generic defect has been recognized and corrective action taken. Attention is also given to engine sensors to verify functioning status. Details of the inspection procedures, unscheduled maintenance, and inspection tools and instruments are provided.